Pharmacological test with nitroglycerin in combination with perfusion SPECT with ^99mTc-Technetril in assessing the viability of ischemic myocardium in patients after acute infarction

Abstract

Aim. To evaluate the possibility of using nitroglycerin sublingually in combination with 99mTc-Technetril cardiac perfusion single-photon emission computed tomography (SPECT) as a test for detecting viable myocardium. Material and methods. 28 male patients with coronary heart disease (CHD) and postinfarction cardiosclerosis were examined. Group 1 included 10 patients with CHD without signs of acute myocardial infarction (AMI). Group 2 comprised 18 patients with CHD, postinfarction cardiosclerosis (PICS). The control group consisted of patients who were subsequently rejected a diagnosis of CHD. Patients took 2 tablets (1 mg) of nitroglycerin sublingually, and then, at the peak of the drug’s action (after 3–5 minutes), they were intravenously administered 370 MBq of 99mTc-Technetril (by Diamed, Russia). Myocardial SPECT with 99mTc-Technetril was performed 1 hour after RFP injection. The next day, myocardial SPECT with 99mTc-Technetril was repeated at rest. Results. When taking tableted nitroglycerin at a dose of 1 mg sublingually, its maximum plasma concentration is on average 0.26 ± 0.04 microcgram/l. It is reached by 110–150 s, then maintained within 10 % of the maximum for 7-9 minutes. Nitroglycerin leads to improvement in global and local contractility and increased LV pumping function in CHD patients. This is most pronounced in individuals with a higher class of angina pectoris after AMI and major changes in intracardiac hemodynamics initially. The nitroglycerin test in combination with 99mTc-Technetril SPECT-CT allowed to identify myocardial areas with improved blood flow and increased EFLV after CABG. Conclusion. The nitroglycerin test in combination with 99mTc-Technetril SPECT-CT is effective for detecting viable myocardium in patients with coronary atherosclerosis and CHD, safe and relatively simple due to the sublingual route of nitroglycerin intake.